The Mk I Variant.
The Mk II Variant.First seen here
The Mk III Variant.Credit goes to Andro Tempest
The Heavy Weapon variant.
The Overseer variant.Credit goes to Rabid Goldfish
Another View.

A little project I'm working on....While most of these Drones Aren't my actual handiwork,I can still say that all of them have been modified in some way.While this is not the final product I'm looking towards,this is a first step.

IMPORTANT 11/27/12
If you are the creators of any of these,I apologize for not giving you credit.
That should be up shortly.